Plastic, resealable elongate valve opening for a vacuum food package

ABSTRACT

A flexible, plastic food package is provided having an elongate opening check valve with an air removal port that allows repeated opening and resealing of the package for removal of air and moisture by vacuuming. The vacuum is established by removing air through the air removal port which encloses a compressible foam material that can be repeatedly penetrated by a blunt-tip aspiration needle associated with a vacuum pump. Following closure of the check valve and inducing a vacuum, the foam material will be compressed to seal the package. The closing force of the valve is sufficient to maintain a vacuum in the package, e.g., −90 kPa at a low temperature of e.g., −60 C for a long period of time. The closing force of the valve can be overcome by hand to enable opening of the food package and access to food therein. Loss of vacuum by migration of air into the package can be reestablished by means of the aspiration needle. The compressed foam in the air removal port will seal along the entry area of the needle when it is withdrawn, and enables repeated use for long periods of time and at extremely low temperatures while still retaining the flavor and edibility of the food due a considerable reduction of ice formation on the frozen food.

BACKGROUND OF THE INVENTION

This invention relates to a new and improved flexible film food package suitable for vacuum storage of frozen fresh or cooked foods at low temperature and for an extended period of time. The food package of this invention allows repeated opening and closing to facilitate the addition and/or removal of food without significant loss of flavor or edibility.

The food packaging industry includes vacuum or non-vacuum sealed food products, many of which packages are intended for use in storage at extremely low temperatures over long periods of time. Products include raw meat, poultry, fish, and other sea foods such as crustaceans, fresh vegetables, fully cooked foods such as pizza, and frozen confections such as ice cream.

The problem with presently designed factory sealed food packages is two fold, the first being that ice is formed on the food content if the package is sealed without vacuum and the second being that no measures are provided to reseal the package for restoring the vacuum following opening of the sealed package for addition of food or for removing a portion of its content. In both cases, when the seal is broken to allow removal and/or addition of food, the entry of air and moisture into the package frequently causes ice formation. The result is a deterioration of the food and a reduction in flavor and edibility. Also the long term storage viability of the food contained therein is reduced upon resealing.

Various patents have been disclosed pertaining to closures and sealing systems for food packages, and they include U.S. Pat. Nos. 4,941,310; 5,009,828; 5,070,584; US 2003/015,2296 A1; U.S. Pat. No. 6,692,147; B2; 2004/011,4837 A1; 2004/016,1178 A1; 2005/019,6077 A1; 2005/024,4083 A1; and, 2007/011,0340 A1l . However, as noted, supra, none of the above patents provide a solution to the problem of ice formation and air and moisture contamination following opening of a food package to access the contents therein. Also, these patents do not provide long term vacuum sealing at very low temperatures.

An inexpensive, flexible, plastic package for vacuum storage of food is desired which enables a user to easily access the contents therein and, to reseal the package for continued, long term storage at extremely low temperatures.

One-way check valves are in common use to allow flow of gas or liquid through a tube or pipe in one direction while blocking in the opposite direction. These check valves are designed to fit a circular opening of a tube or pipe, but not for a flat bag with an elongate opening. This invention relates to a new elongate check valve that fits into an elongate opening of a plastic film food package and for maintaining a vacuum within the package, hence enabling storing fresh or cooked foods at low temperature for a long time. The food package allows repeated opening and closing the check valve followed by restoring a vacuum to facilitate adding and/or removal of food without significant flavor or edibility loss.

A further object is to provide a new and improved method for vacuum containerization of food in a flexible, plastic film package.

THE INVENTION

According to the Invention, there is provided a new and improved vacuum resealable device for a food package comprising an elongate, one-way check valve that runs along the entire opening of the package and an air removal port including a compressed foam sponge installed in a rigid frame between the valve and the interior of the food package opening. Opening of the check valve enables access to the food package for removal and/or addition of food.

After the food package is resealed, air is removed from the package by means of a vacuum pump and an associated blunt-tip, air aspirating needle which is inserted through a bore in the compressed foam in the air removal port. The bore formed in the foam sponge is closed by compression, but enables hand insertion of the aspirating needle therethrough for repeated aspirations to remove air from the food package. The foam sponge is maintained under compression by the rigid frame. When compressed, the foam sponge functions to seal the surrounding bore area along entry and withdrawal lines of the aspirating needle, thereby enabling repeated entry and withdrawal of the aspirating needle and continuing use of the food package. Typically, the one-way check valve installed in the opening of the food package will be closed securely against the rigid valve frames due to the internal vacuum force within the package.

Aspiration will restore the vacuum and reseal the food package to enable storage at extremely low temperatures, e.g., −60 C with minimal ice formation on the stored food contents.

Plastic zippers facilitate closure of the package and also may be used to form the valve frames; adhesive peel strips or sealing clips also may be employed to facilitate opening and closing the food package.

The sidewall structure of the food package comprises a flexible, plastic film material such as low and high density polyethylenes, nylons, polyesters, possibly polyurethanes, and laminates thereof, with sufficient thickness to reduce significant migration of air through the film. Preferred materials of construction of the compressible foam are silicone foam rubbers and possibly polyurethane foams. Other rubber foams may be useful providing they have suitable characteristics similar to those of silicone and polyurethane foams without toxicity. These foam rubbers are listed in the Encyclopedia of Chemical Technology, by Kirk-Othmer, 3^(rd) Edition, 1982 at: Vol. 11, page 78; Vol. 18, page 470; and, Vol. 20, pages 365-368 and 943; ISBN 0-471-02073-7; and incorporated herein by reference;

Periodic inspection of the film package during storage would be appropriate to determine if any migration of air through the plastic sidewalls of the package has occurred, causing a reduction in vacuum. This can be simply rectified by entering the package with the aspirating needle, and in conjunction with the aspirating pump vacuuming out any air, moisture, and ice formation;

The resealable food storage package of this invention represents a significant improvement of frozen food storage that requires repeated open and closure for food retrieval, resealing the package, and restoring a vacuum.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the invention in a closed position and interlocked with a food package;

FIG. 2 Is a side view in axial section of the valve taken along the plane “a” of FIG. 1;

FIG. 3 is a perspective view of the valve frames In an open position with a trough valve leaflet attached to the male valve frame;

FIG. 4A is an isometric view of a compressed foam sponge encased in a housing frame;

FIG. 4B is a side view of uncompressed foam sponge defining a small central bore;

FIG. 4C is a cross sectional side view of the compressed foam sponge tightly encased in the rigid valve housing;

FIG. 4D is an isometric view of a rigid cover of the housing with a central bore in the foam;

FIG. 5 is an isometric view of a plastic liner for use with a square paper carton food container into which is attached a valve of this invention for storage of frozen condiments, cooked food, and the like;

FIG. 6A is an isometric view of a cylindrical container, typically constructed of a paper carton and used for storage of ice cream;

FIG. 6B is an isometric view of a plastic liner for use with the cylindrical carton of FIG. 6A; and,

FIG. 6C is a cross-sectional view of a trough valve of circular shape along the plane “b” of FIG. 6B.

DESCRIPTION OF THE PREFERRED EMBODIMENTS:

The resealable vacuum food package 10 of this invention is shown in FIGS. 1 and 2 interfitting along an open end into the food package and bonded thereto along the open, elongate top portion. The food package 10 is constructed typically of thin-walled, flexible polyethylene film 11, 12 about 3-4 mils thickness with sufficient strength to withstand vacuum pressure and long term air and moisture transmission.

FIG. 1 shows an isometric view of the resealable vacuum package 10, comprising an elongate check valve 10A, air removal foam valve 10B, and two films 11 and 12 of the package 10. Both films 11, 12 are bonded to the check valve 10A. The two films 11, 12 are sealed together along side and bottom edges 13, 14 and 15. Interlocking male and female zipper strips 16,17 are constructed of a flexible, but rigid polymer, e.g., polyethylene. A rear end of the interlocked zipper strips are simply sealed 21, but the front end is sealed to incorporate an air removal foam valve 10B. A valve frame 22 defining an air removal port is made of a rigid polymer, e.g., polycarbonate, which contains a compressed foam sponge 23, made of a silicone rubber, polyurethane, or similar elastic polymer. A small, central bore 24 is closed by compression.

FIG. 2 shows an axial cross-sectional view along the plane “a” of FIG. 1. The male and female zipper strips 16,17 are interlocked, closing the food package 10. Although they are interlocked, they cannot maintain a vacuum in the food package because there is a small space between them. The interlocked zipper strips form a trough-shaped space 27 and a vacuum channel 29, and are connected to each other through an upper groove 28. The interior space 31 of the resealable food package 10 is contiguous with the vacuum channel 29 through a lower groove 30. Elongate check valve leaflets 32, 33 snugly fit into the trough-shaped space 27. A guiding fin 35 of the valve leaflet drips into the upper groove 28, while an alignment bar 34 prevents kinking of the valve leaflets 32, 33. The upper edge of the valve leaflet 36 is bonded to the interior wall of the male zipper strip 16.

Interlocked zipper strips can be separated by pulling peel tabs 25, 26. When the zipper strips are separated, the valve leaflet 43 moves with the male zipper strip 16, thus allowing entry into the package 10 through the opening 44. The elongate check valve leaflet is constructed with a soft, elastic thin polymer membrane, e.g., silicone rubber or polyurethane. It spans the entire length of the zipper strips 16, 17 and both ends to form closed bulges. A guiding fin 32 and alignment bar 34 prevent kinking of the valve leaflet 43 when it is vacuum suctioned into the valve frame. A male interlock 41 fits in a female 42 interlock when the zipper strips are pressed together.

Another embodiment of this invention is shown in FIG. 4A, and provides a foam valve 10B with a rigid frame 22. The central bore 24 of minute caliber is formed in the foam sponge 23 that is made of polyurethane, silicone rubber or similar elastic polymer; FIG. 4B shows an uncompressed sponge 23A and bore 24A. When the foam sponge 23 is compressed, is positioned inside the rigid frame 22, which is constructed of polycarbonate or similar materials, the central bore is compressed and closed 24. A cap 45 made of a similar rigid polymer, e.g., polycarbonate or similar material, defines a central bore 46 for insertion of an aspiration needle, as shown in FIG. 4D. The cap is bonded to the end of the foam sponge valve 10B.

The present invention has possible applications for various types of food storage containers. For instance, a box shape food storage container typically used for storage of cooked food, as shown in FIG. 5, and a cylindrical paper carton container commonly used for ice cream as shown in FIG. 6 might utilize vacuum sealing according to the invention. For a box type container 47, the plastic package with an elongate check valve 10A is bonded to the interior of the box and an air removal port 10B. For a cylindrical paper carton container 48 and 49, a plastic film liner 50 is placed inside the cylindrical paper carton container. A top cover 51 is bonded to the inner circular plastic strip made of a flexible but rigid polymer, e.g., polyethylene.

When a peel tab 52 is pulled, the check valve is lifted from the valve frame formed between the inner circular strip 53 and an outer circular strip 54. This opens the cylindrical package for access to the contents therein. Both circular plastic trips 53 and 54 and the top cover 51 are sealed around the air removal port 10B. When the top cover 51 is placed back and air is aspirated via a foam valve in the air removal port, the cylindrical liner collapses until it is firmly suctioned against the contents in the food package, thereby eliminating air and moisture. 

1. A food package providing a plastic film food container defining an open portion; an elongate opening and closure valve means bonded coextensively along the open portion of the food container and interfitting therewith; an air removal port defined by closure of the valve including sponge means, which upon compression by valve closure, forms a vacuum seal along the open portion of the food container, the sponge means defining a structure including a bore for entry of a blunt tip aspirating needle into the food container; whereby, opening of the elongate valve enables entry to the food container, and following closure of the valve, removal of air and moisture by aspiration with the needle enables a high vacuum to be formed within the food container; the sponge structure enabling repeated opening and closure of the valve for access to the food container and the application of a vacuum, thereby enabling long term use of food in the container at low temperatures and vacuum pressures.
 2. The food package of claim 1, in which the elongate valve provides a sufficient closing force to maintain a vacuum of about −90 kPa and at a low temperature about −20 C to about −60 C.
 3. The food package of claim 2, in which the sponge structure provides about 5-15 repeated insertions of a blunt tip aspiration needle associated with a vacuum pump, thereby inducing a vacuum seal of about −90 kPa.
 4. The food package of claim 1, in which the sponge structure is selected from the group consisting of silicone rubbers, thermoplastic rubbers, synthetic rubbers, and polyurethanes.
 5. The food package of claim 1, in which the plastic material of the food container is selected from the group consisting of low and high density polyethylenes, nylons, polyesters, polyurethanes, and laminates thereof.
 6. The food package of claim 1, in which the aspirating needle is associated with an exhaust pump.
 7. A transparent food package of claim 1, providing visual inspection and tactile monitoring of a vacuum in the package, and upon loss of vacuum, insertion of an aspirating needle into the food package enables removal of air and moisture therefrom.
 8. The food package of claim 1, in which the closure valve is an elongated trough valve.
 9. A valve for interfitting into an open portion of a food container, the valve comprising engaging closure side elements, the closure side elements defining an air removal port for containment of a sponge element, a bore defined within the sponge element for insertion of an aspirating needle therethrough, whereupon closing of the side elements compresses the sponge element to form a vacuum seal between the sponge element and the food container, thereby enabling repeated aspiration of air and moisture from the container to maintain a vacuum therein.
 10. The food package of claim 1, in which the food container includes a paper box and a cylindrical carton.
 11. The food package of claim 1, in which the elongate valve provides a sufficient closing force to maintain a vacuum of at least about −90 kPa, at a low temperature about −20 C to about −60 C for about one year. 